Various torque amplifying (or multiplying) drive trains are in wide usage in a variety of applications (see, for example, U.S. Pat. Nos. 7,311,025, 4,641,887 and 3,203,275). Many shaft rotation speed increasing drive trains are also known and have much in common with the known torque increasing drives. Either type of drive essentially translates speed and torque in a known relationship utilizing various techniques, usually employing various gear based transfers.
In particular, planetary torque multipliers are well known, such systems typically multiplying torque in linearly associated stages. These systems use a sun gear to drive a set of planet gears mounted on a so-called “spider” platform and within a ring gear. The spider platform of one stage provides the input to the sun gear of the next stage in line, each stage multiplying torque. Very large torque values can be developed in this manner. However, as the torque carried through the system increases, each stage requires system gears that are stronger and wider than the last. These requirements add to overall system length, weight and cost, and are often noisy and rough running.
Often space constraints limit the stages allowed in such systems and thus the torque increase available. To ameliorate the space problem, large (and frequently expensive) input drive motors are often required. Alternatively, right angle drives are often utilized where required, and many such mechanisms for translating rotational direction are known (see, for example, U.S. Pat. Nos. 7,513,179, 7,302,873, and 5,125,284). Right angle drive translation saves space, but right angle gears interfaces are often inherently weaker. The transfer of highly amplified radial loads to an output through such interfaces (bevel gear sets, for example) is problematical, resulting in high friction losses and subjecting the gears in the interface to tooth breaking and stripping. Moreover, the very nature of such implementations wherein the input direction and the output direction are at an angle to one another unbalances the mechanism making it inappropriate for some uses as currently conceived. Further improvement in such drive systems could thus still be utilized.